<?php
/**
* SeekQuarry/Yioop --
* Open Source Pure PHP Search Engine, Crawler, and Indexer
*
* Copyright (C) 2009 - 2026 Chris Pollett chris@pollett.org
*
* LICENSE:
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* @author Chris Pollett chris@pollett.org
* @license https://www.gnu.org/licenses/ GPL3
* @link https://www.seekquarry.com/
* @copyright 2009 - 2026
* @filesource
*/
namespace seekquarry\yioop\locale\it\resources;
/**
* Italian specific tokenization code. Typically, tokenizer.php
* either contains a stemmer for the language in question or
* it specifies how many characters in a char gram
*
* @author Chris Pollett
*/
class Tokenizer
{
/**
* Words we don't want to be stemmed
* @var array
*/
public static $no_stem_list = [];
/**
* A list of frequently occurring terms for this locale which should
* be excluded from certain kinds of queries
* @var array
*/
public static $stop_words = [
'http', 'https',
"ad", "al", "allo", "ai", "agli", "all", "agl", "alla",
"alle", "con", "col", "coi", "da", "dal", "dallo", "dai",
"dagli", "dall", "dagl", "dalla", "dalle", "di", "del",
"dello", "dei", "degli", "dell", "degl", "della", "delle",
"in", "nel", "nello", "nei", "negli", "nell", "negl", "nella",
"nelle", "su", "sul", "sullo", "sui", "sugli", "sull", "sugl",
"sulla", "sulle", "per", "tra", "contro", "io", "tu", "lui",
"lei", "noi", "voi", "loro", "mio", "mia", "miei", "mie", "tuo",
"tua", "tuoi", "tue", "suo", "sua", "suoi", "sue", "nostro",
"nostra", "nostri", "nostre", "vostro", "vostra", "vostri",
"vostre", "mi", "ti", "ci", "vi", "lo", "la", "li", "le", "gli",
"ne", "il", "un", "uno", "una", "ma", "ed", "se", "perché",
"anche", "come", "dov", "dove", "che", "chi", "cui", "non", "più",
"quale", "quanto", "quanti", "quanta", "quante", "quello", "quelli",
"quella", "quelle", "questo", "questi", "questa", "queste", "si",
"tutto", "tutti", "a", "c", "e", "i", "l", "o", "ho", "hai", "ha",
"abbiamo", "avete", "hanno", "abbia", "abbiate", "abbiano", "avrò",
"avrai", "avrà", "avremo", "avrete", "avranno", "avrei", "avresti",
"avrebbe", "avremmo", "avreste", "avrebbero", "avevo", "avevi",
"aveva", "avevamo", "avevate", "avevano", "ebbi", "avesti", "ebbe",
"avemmo", "aveste", "ebbero", "avessi", "avesse", "avessimo",
"avessero", "avendo", "avuto", "avuta", "avuti", "avute", "sono",
"sei", "è", "siamo", "siete", "sia", "siate", "siano", "sarò",
"sarai", "sarà", "saremo", "sarete", "saranno", "sarei", "saresti",
"sarebbe", "saremmo", "sareste", "sarebbero", "ero", "eri", "era",
"eravamo", "eravate", "erano", "fui", "fosti", "fu", "fummo",
"foste", "furono", "fossi", "fosse", "fossimo", "fossero",
"essendo", "faccio", "fai", "facciamo", "fanno", "faccia",
"facciate", "facciano", "farò", "farai", "farà", "faremo",
"farete", "faranno", "farei", "faresti", "farebbe", "faremmo",
"fareste", "farebbero", "facevo", "facevi", "faceva", "facevamo",
"facevate", "facevano", "feci", "facesti", "fece", "facemmo",
"faceste", "fecero", "facessi", "facesse", "facessimo", "facessero",
"facendo", "sto", "stai", "sta", "stiamo", "stanno", "stia",
"stiate", "stiano", "starò", "starai", "starà", "staremo",
"starete", "staranno", "starei", "staresti", "starebbe", "staremmo",
"stareste", "starebbero", "stavo", "stavi", "stava", "stavamo",
"stavate", "stavano", "stetti", "stesti", "stette", "stemmo",
"steste", "stettero", "stessi", "stesse", "stessimo", "stessero",
"stando"
];
/**
* Storage used in computing the stem
* @var string
*/
private static $buffer;
/**
* Storage used in computing the starting index of region R1
* @var int
*/
private static $r1_start;
/**
* Storage used in computing the starting index of region R2
* @var int
*/
private static $r2_start;
/**
* Storage used in computing the starting index of region RV
* @var int
*/
private static $rv_start;
/**
* Storage used in computing region R1
* @var string
*/
private static $r1_string;
/**
* Storage used in computing region R2
* @var string
*/
private static $r2_string;
/**
* Storage used in computing Region RV
* @var string
*/
private static $rv_string;
/**
* Storage for computing the starting position for the longest suffix
* @var int
*/
private static $max_suffix_pos;
/**
* Storage used in determinig if step1 removed any endings from the word
* @var bool
*/
private static $step1_changes;
/**
* This method currently does nothing. For some locales it could
* used to split strings of the form "thisisastring" into a string
* with the words separated: "this is a string"
*
* @param string $pre_segment string to be segmented
* @return string after segmentation done (same string in this case)
*/
public static function segment($pre_segment)
{
return $pre_segment;
}
/**
* Removes the stop words from the page (used for Word Cloud generation)
*
* @param mixed $data either a string or an array of string to remove
* stop words from
* @return mixed $data with no stop words
*/
public static function stopwordsRemover($data)
{
static $pattern = "";
if (empty($pattern)) {
$pattern = '/\b(' . implode('|', self::$stop_words) . ')\b/u';
}
$data = preg_replace($pattern, '', $data);
return $data;
}
/**
* Computes the stem of an Italian word
* Example guardando,guardandogli,guardandola,guardano all stem to guard
*
* @param string $word is the word to be stemmed
* @return string stem of $word
*/
public static function stem($word)
{
self::$buffer = $word;
self::$step1_changes = false;
self::$max_suffix_pos = -1;
self::prelude();
self::step0();
self::step1();
self::step2();
self::step3a();
self::step3b();
self::postlude();
return self::$buffer;
}
/**
* Checks if a string is a suffix for another string
*
* @param $parent_string is the string in which we wish to find the suffix
* @param $substring is the suffix we wish to check
* @return int $pos as the starting position of the suffix $substring in
* $parent_string if it exists, else false
*/
private static function checkForSuffix($parent_string,$substring)
{
$pos = strrpos($parent_string,$substring);
if ($pos !== false &&
(strlen($parent_string) - $pos == strlen($substring)))
return $pos;
else
return false;
}
/**
* Checks if a string occurs in another string
*
* @param string $string is the parent string
* @param string $substring is the string checked to be a sub-string
* of $string
* @return bool if $substring is a substring of $string
*/
private static function in($string, $substring)
{
$pos = strpos(($string ?? ""), $substring);
if ($pos !== false) {
return true;
} else {
return false;
}
}
/**
* Computes the starting index for region R1
*
* @param string $string for which we wish to find the index
* @return int $r1_start as the starting index for R1 for $string
*/
private static function r1($string)
{
$r1_start = -1;
for ($i = 0; $i < strlen($string); $i++){
if ($i >= 1){
if (self::isVowel($string[$i - 1]) &&
!self::isVowel($string[$i])){
$r1_start = $i + 1;
break;
}
}
}
if ($r1_start != -1){
if ($r1_start > strlen($string) - 1)
$r1_start = -1;
else{
if ($string[$r1_start] == "`")
$r1_start += 1;
}
}
return $r1_start;
}
/**
* Computes the starting index for region R2
*
* @param string $string for which we wish to find the index
* @return int $r2_start as the starting index for R1 for $string
*/
private static function r2($string)
{
$r2_start = -1;
$r1_start = self::r1($string);
if ($r1_start !== -1) {
$len = strlen($string);
for ($i = $r1_start; $i < $len; $i++) {
if ($i >= $r1_start + 1){
if (self::isVowel($string[$i - 1]) &&
!self::isVowel($string[$i])) {
$r2_start = $i + 1;
break;
}
}
}
}
if ($r2_start != -1){
if ($r2_start > strlen($string) - 1) {
$r2_start = -1;
} else {
if ($string[$r2_start] == "`") {
$r2_start += 1;
}
}
}
return $r2_start;
}
/**
* Computes the starting index for region RV
*
* @param string $string for which we wish to find the index
* @return int $rv_start as the starting index for RV for $string
*/
private static function rv($string)
{
$i = 0;
$j = 1;
$rv_start = -1;
$length = strlen($string);
if ($length <= 2)
$rv_start = -1;
else{
if (self::isVowel($string[$j])){
if (self::isVowel($string[$i])){
for ($k = $j + 1; $k < $length; $k++){
if (!self::isVowel($string[$k])){
$rv_start = $k + 1;
break;
}
}
} else {
$rv_start = 3;
}
} else {
for ($k = $j + 1; $k < $length; $k++){
if (self::isVowel($string[$k])){
$rv_start = $k + 1;
break;
}
}
}
}
if ($rv_start != -1){
if ($rv_start >= $length)
$rv_start = -1;
else{
if ($string[$rv_start] == "`")
$rv_start += 1;
}
}
return $rv_start;
}
/**
* Computes regions R1, R2 and RV in the form
* strings. $r1_string, $r2_string, $r3_string for R1,R2 and R3
* repectively
*/
private static function getRegions()
{
if ((self::$r1_start = self::r1(self::$buffer)) != -1) {
self::$r1_string = substr(self::$buffer, self::$r1_start);
} else {
self::$r1_string = null;
}
if ((self::$r2_start = self::r2(self::$buffer)) != -1) {
self::$r2_string = substr(self::$buffer, self::$r2_start);
} else {
self::$r2_string = null;
}
if ((self::$rv_start = self::rv(self::$buffer)) != -1) {
self::$rv_string = substr(self::$buffer, self::$rv_start);
} else {
self::$rv_string = null;
}
}
/**
* Checks if a character is a vowel or not
*
* @param string $char is the character to be checked
* @return bool if $char is a vowel
*/
private static function isVowel($char)
{
return match ($char) {
"U", "I", "`" => false,
"a", "e", "i", "o", "u" => true,
default => null,
};
}
/**
* Computes the longest suffix for a given string from a given set of
* suffixes
*
* @param string $string for which the maximum suffix is to be found
* @param array $suffixes an array of suffixes
* @return int $max_suffix is the longest suffix for $string
*/
private static function maxSuffix($string, $suffixes)
{
$string ??= "";
$max_length = 0;
$max_suffix = "";
foreach ($suffixes as $suffix) {
$pos = strrpos($string, $suffix);
if ($pos !== false) {
$string_tail = substr($string, $pos);
$suffix_length = strlen($suffix);
if (!strcmp($string_tail, $suffix)){
if ($suffix_length > $max_length){
$max_suffix = $suffix;
$max_length = $suffix_length;
self::$max_suffix_pos = $pos;
}
}
}
}
return $max_suffix;
}
/**
* Replaces all acute accents in a string by grave accents and also handles
* accented characters
*
* @param string $string in which the acute accents are to be
* replaced
* @return string with changes
*/
private static function acuteByGrave($string)
{
$pattern2 = ["/á/","/é/","/ó/","/ú/","/è/",
"/ì/","/ò/","/ù/", "/à/","/í/"];
$replacement = ["a`","e`","o`","u`","e`",
"i`","o`","u`","a`","i`"];
$string = preg_replace($pattern2,$replacement,$string);
return($string);
}
/**
* Performs the following functions:
* Replaces acute accents with grave accents
* Marks u after q and u,i preceded and followed by a vowel as a non vowel
* by converting to upper case
*/
private static function prelude()
{
$pattern_array = ["/Qu/","/qu/"];
$replacement_array = ["QU","qU"];
//Replace acute accents by grave accents
self::$buffer = self::acuteByGrave(self::$buffer);
/**
* Convert u preceded by q and u,i preceded and followed by vowels
* to upper case to mark them as non vowels
*/
self::$buffer = preg_replace($pattern_array,$replacement_array,
self::$buffer);
for ($i = 0; $i < strlen(self::$buffer) - 1; $i++){
if ($i >= 1 && (self::$buffer[$i] == "i" ||
self::$buffer[$i] == "u")){
if (self::isVowel(self::$buffer[$i-1]) &&
self::isVowel(self::$buffer[$i+1]) &&
self::$buffer[$i+1] !== '`')
self::$buffer[$i] = strtoupper(self::$buffer[$i]);
}
}
}
/**
* Handles attached pronoun
*/
private static function step0()
{
$max = 0;
$suffixes = ["ci","gli","la","le","li","lo",
"mi","ne","si","ti","vi","sene",
"gliela","gliele","glieli","glielo",
"gliene","mela","mele","meli","melo",
"mene","tela","tele","teli","telo",
"tene","cela","cele","celi","celo",
"cene","vela","vele","veli","velo","vene"];
$phrases = ["ando","endo","ar","er","ir"];
//Get R1, R2, RV
self::getRegions();
//Find the maximum length suffix in the string
$max_suffix = self::maxSuffix(self::$rv_string,$suffixes);
if ($max_suffix != "") {
$sub_string = substr(self::$rv_string, 0, -strlen($max_suffix));
foreach ($phrases as $phrase) {
if (self::checkForSuffix($sub_string,$phrase) !== false){
switch ($phrase) {
case "ando":
case "endo":
self::$buffer = substr_replace(self::$buffer, "",
self::$rv_start + self::$max_suffix_pos,
strlen($max_suffix));
break;
case "ar":
case "er":
case "ir":
self::$buffer = substr_replace(self::$buffer, "e",
self::$rv_start + self::$max_suffix_pos,
strlen($max_suffix));
break;
}
}
}
}
}
/**
* Handles standard suffixes
*/
private static function step1()
{
$suffixes = ["anza","anze","ico","ici","ica",
"ice","iche","ichi","ismo","ismi",
"abile","abili","ibile","ibili","ista",
"iste","isti","ista`","iste`","isti`",
"oso","osi","osa","ose","mente","atrice",
"atrici","ante","anti","azione","azioni",
"atore","atori","logia","logie","uzione",
"uzioni","usione","usioni","enza","enze",
"amento","amenti","imento","imenti","amente",
"ita`","ivo","ivi","iva","ive"];
//Get R1,R2 and RV
self::getRegions();
//Find the longest suffix
$max_suffix = self::maxSuffix(self::$buffer, $suffixes);
//Handle suffix according
switch ($max_suffix) {
case "anza":
// no break
case "anze": case "ico": case "ici": case "ica":
case "ice": case "iche": case "ichi": case "ismo": case "ismi":
case "abile": case "abili": case "ibile": case "ibili":
case "ista": case "iste": case "isti": case "ista`": case "iste`":
case "isti`": case "oso": case"osi": case "osa": case "ose":
case "mente": case "atrice": case "atrici": case "ante":
case "anti":
//Delete if in R2
if (self::in(self::$r2_string, $max_suffix)){
self::$buffer = substr_replace(self::$buffer,"",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
break;
case "azione":
// no break
case "azioni":
case "atore":
case "atori":
//Delete if in R2
if (self::in(self::$r2_string, $max_suffix)){
self::$buffer = substr_replace(self::$buffer, "",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
self::getRegions();
//If preceded by ic, delete if in R2
if (self::checkForSuffix(self::$buffer,"ic")) {
if (self::in(self::$r2_string, "ic")){
self::$buffer = str_replace("ic", "", self::$buffer);
self::$step1_changes = true;
}
}
break;
case "logia":
// no break
case "logie":
//Replace with log if in R2
if (self::in(self::$r2_string, $max_suffix)) {
self::$buffer = substr_replace(self::$buffer, "log",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
break;
case "uzione":
// no break
case "uzioni": case "usione": case "usioni":
//Replace with u if in R2
if (self::in(self::$r2_string, $max_suffix)) {
self::$buffer = substr_replace(self::$buffer,"u",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
break;
case "enza":
// no break;
case "enze":
//Replace with ente if in R2
if (self::in(self::$r2_string, $max_suffix)) {
self::$buffer = substr_replace(self::$buffer,"ente",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
break;
case "amento":
// no break
case "amenti": case "imento": case "imenti":
//Delete if in RV
if (self::in(self::$rv_string, $max_suffix)){
self::$buffer = substr_replace(self::$buffer,"",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
break;
case "amente":
//Delete if in R1
if (self::in(self::$r1_string, $max_suffix)){
self::$buffer = substr_replace(self::$buffer,"",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
self::getRegions();
//Check if preceded by iv, if yes, delete if in R2
if (self::checkForSuffix(self::$buffer,"iv")){
if (self::in(self::$r2_string, "iv")){
self::$buffer = str_replace("iv", "", self::$buffer);
self::$step1_changes = true;
if (self::checkForSuffix(self::$buffer,"at")){
if (self::in(self::$r2_string,"at")){
self::$buffer = str_replace("at","",
self::$buffer);
self::$step1_changes = true;
}
}
}
} else {
/**
* Otherwise check if preceded by os,ic or abil, if yes,
* delete if in r2
*/
self::getRegions();
$further = ["os","ic","abil"];
foreach ($further as $suffix){
$pos = self::checkForSuffix(self::$buffer, $suffix);
if ($pos !== false){
if (self::in(self::$r2_string, $suffix)){
self::$buffer = substr_replace(self::$buffer,
"",$pos);
self::$step1_changes = true;
}
}
}
}
break;
case "ita`":
//Delete if in R2
if (self::in(self::$r2_string,$max_suffix)){
self::$buffer = substr_replace(self::$buffer,"",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
//If further preceded by abil,ic or iv, delete if in R2
self::getRegions();
$further = ["abil","ic","iv"];
foreach ($further as $suffix){
if (self::checkForSuffix(self::$buffer,$suffix)){
if (self::in(self::$r2_string,$suffix)){
self::$buffer = str_replace($suffix,"",
self::$buffer);
self::$step1_changes = true;
}
}
}
// no break
case "ivo":
// no break
case "ivi":
case "iva":
case "ive":
//Delete if in R2
if (self::in(self::$r2_string, $max_suffix)){
self::$buffer = substr_replace(self::$buffer,"",
self::$max_suffix_pos,strlen($max_suffix));
self::$step1_changes = true;
}
//If preceded by at, delete if in R2
self::getRegions();
$pos = self::checkForSuffix(self::$buffer,"at");
if ($pos !== false){
if (self::in(self::$r2_string, "at")) {
self::$buffer = substr_replace(self::$buffer,
"", $pos, 2);
self::$step1_changes = true;
//If further preceded by ic, delete if in R2
self::getRegions();
$pos = self::checkForSuffix(self::$buffer, "ic");
if ($pos !== false) {
if (self::in(self::$r2_string, "ic")) {
self::$buffer = substr_replace(self::$buffer,
"", $pos, 2);
self::$step1_changes = true;
}
}
}
}
}
}
/**
* Handles verb suffixes
*/
private static function step2()
{
$verb_suffixes = ["ammo","ando","ano","are","arono","asse",
"assero","assi","assimo","ata","ate","ati",
"ato","ava","avamo","avano","avate","avi","avo",
"emmo","enda","ende","endi","endo","era`",
"erai","eranno","ere","erebbe","erebbero",
"erei","eremmo","eremo","ereste","eresti",
"erete","ero`","erono","essero","ete","eva",
"evamo","evano","evate","evi","evo","Yamo",
"iamo","immo","ira`","irai","iranno","ire",
"irebbe","irebbero","irei","iremmo","iremo",
"ireste","iresti","irete","iro`","irono","isca",
"iscano","isce","isci","isco","iscono","issero",
"ita","ite","iti","ito","iva","ivamo","ivano",
"ivate","ivi","ivo","ono","uta","ute","uti",
"uto","ar","ir"];
/**
* If no ending was removed in step1, find the longest suffix from the
* above suffixes and delete if in RV
*/
if (!self::$step1_changes) {
//Get R1,R2 and RV
self::getRegions();
$max_suffix = self::maxSuffix(self::$rv_string, $verb_suffixes);
if ($max_suffix != "" && self::in(self::$rv_string, $max_suffix))
self::$buffer = substr_replace(self::$buffer,"",
self::$rv_start + self::$max_suffix_pos,
strlen($max_suffix));
}
}
/**
* Deletes a final a,e,i,o,a`,e`,i`,o` and a preceding i if in RV
*/
private static function step3a()
{
$vowels = array ("a","e","i","o","a`","e`","i`","o`");
//Get R1,R2 and RV
self::getRegions();
//If a character from the above is found in RV, delete it
foreach ($vowels as $character) {
$pos = self::checkForSuffix(self::$buffer,$character);
if ($pos !== false){
if (self::in(self::$rv_string,$character)){
self::$buffer = substr_replace(self::$buffer, "", $pos,
strlen($character));
break;
}
}
}
//If preceded by i, delete if in RV
self::getRegions();
$pos = self::checkForSuffix(self::$buffer,"i");
if ($pos !== false){
if (self::in(self::$rv_string,"i"))
self::$buffer = substr_replace(self::$buffer,"",$pos,1);
}
}
/**
* Replaces a final ch/gh by c/g if in RV
*/
private static function step3b()
{
//Get R1,R2 and RV
self::getRegions();
//Replace final ch/gh with c/g if in RV
$patterns = ["ch","gh"];
foreach ($patterns as $pattern) {
switch ($pattern) {
case "ch":
$pos = self::checkForSuffix(self::$buffer,$pattern);
if ($pos !== false){
if (self::in(self::$rv_string,$pattern))
self::$buffer = substr_replace(self::$buffer,
"c",$pos);
}
break;
case "gh":
$pos = self::checkForSuffix(self::$buffer,$pattern);
if ($pos !== false){
if (self::in(self::$rv_string,$pattern))
self::$buffer = substr_replace(self::$buffer,
"g",$pos);
}
break;
}
}
}
/**
* Converts U and/or I back to lowercase
*/
private static function postlude()
{
$pattern_array_1 = ["/U/","/I/"];
$replacement_array_1 = ["u","i"];
$pattern_array_2 = ["/a`/","/e`/","/i`/","/o`/","/u`/"];
$replacement_array_2 = ["à","è","ì","ò","ù"];
self::$buffer = preg_replace($pattern_array_1, $replacement_array_1,
self::$buffer);
self::$buffer = preg_replace($pattern_array_2, $replacement_array_2,
self::$buffer);
}
}
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